Kinematic differences between NLS1 and BLAGN sources

It is well-known that the higher policyclic aromatic hydrocarbon (PAH) abundance, lower black hole mass, higher accretion rate and lower luminosities are among the major characteristics of Narrow-Line Seyfert galaxies (NLS1), when they are compared to Broad line Seyfert galaxies (BLS1). NLS1s may be normal Seyfert galaxies at an early stage of evolution, their black holes may still be growing and/or they could be special for some other reason. In this work we discuss the findings that NLS1s have most of line and continuum luminosities correlated with FWHM(H$\beta$), which may be the trace of their rapid black hole mass grow. BLS1 do not show such trends. Also, PAHs may be destroyed as the black hole grows and the starbursts are removed, for NLS1 objects.Comment: Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe - NLS1 Padov

The combined method for uncertainty evaluation in electromagnetic radiation measurement

Electromagnetic radiation of all frequencies represents one of the most common and fastest growing environmental influence. All populations are now exposed to varying degrees of electromagnetic radiation and the levels will continue to increase as technology advances. An electronic or electrical product should not generate electromagnetic radiation which may impact the environment. In addition, electromagnetic radiation measurement results need to be accompanied by quantitative statements about their accuracy. This is particularly important when decisions about product specifications are taken. This paper presents an uncertainty budget for disturbance power measurements of the equipment as part of electromagnetic radiation. We propose a model which uses a mixed distribution for uncertainty evaluation. The evaluation of the probability density function for the measurand has been done using the Monte Carlo method and a modified least-squares method (combined method). For illustration, this paper presents mixed distributions of two normal distributions, normal and rectangular, respectively

Extending the Role of Computational Fluid Dynamics in Screw Machines

Previous publications show that computational fluid dynamics (CFD) can be readily used for the flow prediction and analysis of screw compressors. Several case studies are presented in this article to show the scope and applicability of such methods. These include solid–fluid interaction in screw compressors, prediction of flow generated noise in screw machines, cavitation modelling in gear pumps, and flow in multiphase pumps for oil and gas industry. Numerical grids for all these cases were generated by the authors using an in-house grid generator, while the CFD calculations were performed with a variety of commercially available CFD codes. In order to validate the accuracy of the CFD calculations, an extended test programme was carried out using laser Doppler velocimetry to measure the mean and fluctuating velocity distribution in screw compressor flow domains. The measurement results are then compared with the CFD simulations. The results confirm the viability of the developed techniques. It is shown in this publication that the flexibility of the developed method creates further opportunities for a broader use of CFD for analysis of twin screw machines in a range of new applications

Graph Signal Processing: Overview, Challenges and Applications

Research in Graph Signal Processing (GSP) aims to develop tools for processing data defined on irregular graph domains. In this paper we first provide an overview of core ideas in GSP and their connection to conventional digital signal processing. We then summarize recent developments in developing basic GSP tools, including methods for sampling, filtering or graph learning. Next, we review progress in several application areas using GSP, including processing and analysis of sensor network data, biological data, and applications to image processing and machine learning. We finish by providing a brief historical perspective to highlight how concepts recently developed in GSP build on top of prior research in other areas.Comment: To appear, Proceedings of the IEE

Analytical Grid Generation for accurate representation of clearances in CFD for Screw Machines

One of the major factors affecting the performance prediction of twin screw compressors by use of computational fluid dynamics (CFD) is the accuracy with which the leakage gaps are captured by the discretization methods. The accuracy of mapping leakage flows can be improved by increasing the number of grid points on the profile. However, this method faces limitations when it comes to the complex deforming domains of a twin screw compressor because the computational time increases tremendously. In order to address this problem, an analytical grid distribution procedure is formulated that can independently refine the region of high importance for leakage flows in the interlobe space. This paper describes the procedure of analytical grid generation with the refined mesh in the interlobe area and presents a test case to show the influence of the mesh refinement in that area on the performance prediction. It is shown that by using this method, the flow domains in the vicinity of the interlobe gap and the blowhole area are refined which improves accuracy of leakage flow predictions

Tidal variability of the motion in the Strait of Otranto

Various current data, collected in the Strait of Otranto during the period 1994–2007, have been analysed with the aim of describing the characteristics of the tidal motions and their contribution to the total flow variance. The principal tidal constituents in the area were the semi-diurnal (M2) and the diurnal (K1), with the latter one predominant. The total flow was, in general, more energetic along the flanks than in the middle of the strait. Specifically, it was most energetic over the western shelf and in the upper layer along the eastern flank. In spite of the generally low velocities (a few cm s⁻¹) of the principal tidal constituents, the tidal variance has a pattern similar to that of the total flow variance, that is, it was large over the western shelf and low in the middle. The proportion of non-tidal (comprising the inertial and sub-inertial low-frequency bands) to tidal flow variances was quite variable in both time and space. The low-frequency motions dominated over the tidal and inertial ones in the eastern portion of the strait during the major part of the year, particularly in the upper and intermediate layers. In the deep, near-bottom layer the variance was evenly distributed between the low frequency, diurnal and semi-diurnal bands. An exception was observed near the western shelf break during the summer season when the contribution of the tidal signal to the total variance reached 77%. This high contribution was mainly due to the intensification of the diurnal signal at that location at both upper and bottom current records (velocities of about 10 cm s⁻¹). Local wind and sea level data were analysed and compared with the flow to find the possible origin of this diurnal intensification. Having excluded the sea-breeze impact on the intensification of the diurnal tidal signal, the most likely cause remains the generation of the topographically trapped internal waves and the diurnal resonance in the tidal response. These waves were sometimes generated by the barotropic tidal signal in the presence of summer stratification and the strong bottom slope. This phenomenon may stimulate diapycnal mixing during the stratified season and enhance ventilation of the near-bottom layers

The Action of Hydrazines upon \u27Thiazolidine-4-carboxylic Acids I. Preparation of D-Penicillamine from D-Benzylpenilloic Acid

In the reaction of phenylhydrazine with n-benzylpenilloic acids (Ia or Ila) n-penicillamine was obtained in high yield and purity. The lack of reactivity of N-acyl derivatives (Ib or Ub) with phenylhydrazine indicated that the above reaction proceeded through the open chain imine tautomer of Ia or Ila (IV). The epim~risation of n-benzylpenilloic acid (Ia and Ha) in aprotic solvents was studied by using PMR spectroscopy

Ring Expansion of Thiazolidine and Nucleophilic Substitution in N-Acyl Derivatives of 6-Thia-3,8-diazabicyclo[3.2.1. ]octan-2-one

Reaction of N3,N8-diacyl 6-thia-3,8-diazabicyclo/3.2. l./octan-2- -one (I) with PC15 or S02Cl2 gave 6-chloro substituted N2,N5-diacyl 7-thia-2,5-diazabicyclo/2.2.2./octan-3-one (II). Treatment of II with water yielded the 6-hydroxy derivative (III) while reaction with methanol gave the 6-methoxy derivative (IV). Under the same reaction conditions the mono N8-acyl derivative (V) gave a mixture of 6-substituted 7-thia-2,5-diazabicyclo/2.2.2./octan-3-one and 4- -su bsti tuted 6-thia-3,8-diazabicyclo/3.2. l ./octan-2-one derivatives (XIV and XV; VI and VII; VIII and IX). It was proposed that ring expansion of thiazolidine and nucleophilic substitution occured vi a the thiiranium ion XIII as a common intermediate